From the contemporary standpoints of environmental protection and space saving, it is strongly desired in the medical imaging field to reduce the quantity of spent solution. Needed in this regard is a technology relating to thermographic photosensitive materials for use in medical diagnosis and general photography which can be effectively exposed by means of laser image setters and laser imagers and produce distinct black-and-white images having a high resolution and sharpness. These thermographic photosensitive materials offer to the customer a simple thermographic system which eliminates a need for solution type chemical agents and is not detrimental to the environment.
Medical images must be consistently produced to the desired tone since the image tone has some influence on diagnosis. The photothermographic material, however, has the problem that depending on the humidity condition under which the material is kept prior to thermal development, the resulting image changes its tone. The method capable of overcoming this problem has never been available.